Abstract: Objective：To investigate whether plasma levels of low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) are associated with coronary flow reserve (CFR) in patients with type 2 diabetes mellitus (DM). Methods: Between October 2007 and March 2012，we continuously enrolled 200 participants registered to Department of Cardiology, Peking University Third Hospital, who were divided into 2 groups: DM group (n=95) and control group (n=105). Quantification of CFR was administrated after rest and after adenosine by noninvasive Doppler echocardiography in all the subjects. The CFR, which was performed in the distal part of left descending artery, was used as an indicator of coronary endothelial dysfunction. Results: The plasma levels of LDL-C were significantly higher in the patients with DM than in the controls ［(3.05±0.73) mmo/L vs. (2.74±0.72) mmo/L, P=0.003)］, while the plasma levels of HDL-C were significantly lower in the patients with DM than in the controls ［(1.08±0.24) mmo/L vs. (1.17±0.29) mmo/L, P=0.044］. Furthermore, a lower CFR value was seen in the patients with DM than in the controls ［(2.74±0.63) vs. (3.20±0.69), P<0.001］. The plasma levels of LDL-C were negatively correlated with the CFR values in all the subjects (r=-0.17, P=0.015) and in the DM group (r=-0.23, P=0.021). The LDL-C remained independently correlated with the CFR in the DM group (P=0.036). However，no significantly correlation was found between HDL-C and CFR in the DM group or in all the subjects. Conclusion: LDL-C is independently associated with CFR in patients with diabetic mellitus.

Key words: Diabetes mellitus, type 2, Coronary circulation, Cholesterol, LDL, Blood flow velocity, Cholesterol, HDL